This invention relates to a method and apparatus for conveying flat articles, particularly confectionary items, such as biscuits, from a baking oven to an article processing apparatus, such as a packing machine.
In the large-scale production of biscuits, the latter are conveyed to a packing machine from a stacking device arranged at the discharge end of a baking oven. The conveyor apparatus usually comprises a plurality of parallel-arranged conveyor troughs, such as vibratory conveyor troughs or conveyor belts. The conveyor troughs have a certain capacity for article accumulation so that short-term down periods of the packing machine may be compensated for without the need to direct the biscuits--which are continuously discharged from the oven--into a waste container.
In a known conveyor apparatus according to United Kingdom Pat. Nos. 2,001,608, 2,093,225 and 891,543 the above-noted storage (article accumulation) capacity is limited, particularly in case pressure-sensitive biscuits such as "cream crackers" are to be conveyed.
The conveyor apparatus disclosed in United Kingdom Pat. No. 2,001,608 has two separately driven partial conveyor tracks and an accumulating track provided therebetween. A friction wheel presses down onto the string of biscuits and thus enhances the conveying effect of the conveyor belt. The pressure force of the friction wheel is regulated by sensors which respond to the extent of inclination of the biscuits. In case the operation of an associated packing machine is interrupted, the biscuits are accumulated on the running conveyor belt. Dependent upon the length of accumulation, the pressure may reach such a magnitude that the delicate biscuits are crushed. Consequently, the capacity of accumulation of such an apparatus is also limited.
United Kingdom Pat. No. 2,093,225 discloses a conveyor apparatus in which a conveyor belt discharges the articles into a downwardly bent, stationary chute. In case of an interruption of the operation of the associated packing machine, the biscuits in the column accumulate and the column arches away from the bottom of the chute. An optical barrier measures such a motion and regulates the speed of the conveyor belt with a measuring signal. While with such an arrangement the problem of accumulation at the inlet of the packing machine is resolved, such problem is shifted, however, to the inlet end of the conveyor belt so that, as a result, this conveyor apparatus too, has only a limited capacity for article accumulation.
United Kingdom Pat. No. 891,543 discloses an apparatus in which the conveyor for the biscuit column is subdivided into two separately driven partial tracks. Above the frontal (downstream) track there is arranged a sensor which actuates a dosing device in case of a steep inclination of the biscuits on that track. Above a stationary trough situated between the partial tracks there is arranged a further sensor which, in case of a standstill of the biscuits, switches off the drive of the upstream partial track and, at the same time, actuates a gate which guides the biscuits discharged from the baking oven, to a standby packing machine. Because of the relatively small storage capacity, this system thus needs an additional packing machine which involves substantial expense.